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Welcome to my personal homepage! If you are here to use the X-ray source quick viewer that I create for the Chandra and XMM-Newton source catalogs, please click here.
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Research Assistant Professor
Department of Physics & Institute for the Study of Earth, Oceans, and Space
University of New Hampshire
245C Morse Hall
8 College Road
Durham, NH 03824-2600
U.S.A.
dacheng@dachenglin.com
www.dachenglin.com
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Educational Background:
- 2009 Ph.D. - Physics, Massachusetts Institute of Technology
- 2003 B.S. - Geophysics, University of Science and Technology of China
Research Interests:- The accretion process around black holes across mass scale: black-hole X-ray binaries, ultra-luminous X-ray sources, AGN
- Tidal disruption events (Tidal disruption of stars by otherwise dormant supermassive black holes)
- Search for intermediate-mass black holes of mass 100--100,000 solar mass
- Catalog studies
- The accretion process in neutron-star low-mass X-ray binaries and properties of dense matter
Recent News:
@@@Hubble Finds Best Evidence for Elusive Mid-Sized Black Hole
The new Hubble image confirmed that J2150 is in an extended massive star cluster on the outskirts of a distant galaxy, thus providing strong support that it is a long-sought-after mid-size black hole, which was caught in a tidal disruption event. For more information: NASA/Hubble and ESA/Hubble press releases and the Astrophysical Journal Letters paper. @@@Star Shredded by Rare Breed of Black HoleWe have discovered the best-ever candidate for a very rare and elusive type of cosmic phenomenon: a medium-weight black hole in the process of taring apart feasting on a nearby star. For more information: ESA/XMM-Newton and NASA/Chandra press releases, and the Nature Astronomy paper
@@@My two XMM-Newton/HST proposals are just accepted with priority A! See the AO17 result.
@@@Black Hole Meal Sets Record for Duration and Size- A supermassive black hole in a small galaxy 1.8 billion light years away has been partaking in a decade-long binge of a star.
- This is known as a tidal disruption event and happens when an object gets too close to a black hole and is torn apart by gravity.
- Other similar events have been seen before but this one is much longer, representing an unusually massive meal.
@@@A Wandering Massive Black Hole Caught Shredding a Star
Within this optical light image from the Hubble Space Telescope, the massive black hole and its host galaxy are in the box in the upper left. The inset on the left is a close-up view of the galaxy, with what may be the source associated with this black hole circled. The inset on the right is Chandra’s X-ray image of the massive black hole.
More information, click here. The paper can be found here.
@@@Strong Heartbeat-Like Signals from Gorging Supermassive Black Hole
The XMM-Newton space observatory from European
Space Agency detected an extremely rare heartbeat-like X-ray pulsation
signal from a black hole of 100,000 times that of the
sun at the center of a galaxy at a distance of 1.7 billion light years.
The black hole was gorging on matter at the highest possible rate. Such
signals are common in small black holes with mass less than 20 times
that of the sun, but are very rare among supermassive black holes. Only
two cases were reported before, but with much weaker signals.
The pulse rate is once per 3.8 hours (see the figure above), much lower
than those in small black holes, just like smaller animals have higher
heart rates!
More information, click here. The paper can be found here.
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